Defective Wallpaper

This page discusses the defects and errors that may be found in wallpaper and other wallcoverings.

Damaged edge:  generally caused by improper handling either by the carrier from factory to supplier or from supplier to installer.  Many times the edges are only damaged within the first turns of the wallpaper, but that should not be a huge problem.  

Scalloped edge:  result of the trimmers in the factory moving back and forwards as the wallpaper is passing through. This results in the seams weaving in and out when they are supposed to be cut perfectly straight. The installer should identify this problem within the first roll hung, the remaining product should be returned to the supplier for replacement.

White edge:  a common problem that is especially evident when installing dark colored background wallcoverings because the edges show white when butted together. White edges are caused when the steel at the factory is either dull or is slightly tilted towards the center of the strip, the edges, prior to installation, are actually beveled leaving the substrate or backing of the wallpaper exposed at the edge.  When two strips are joined together this problem is magnified.  After installation, color white seams with colored chalk or permanent water colors of a similar color to the background of the paper.  If either of these remedies are unacceptable, the remaining wallpaper should be returned to the supplier for replacement.  Note:  seams may be apparent after the installation process due to expansion/contraction factors inherent to the installation process and are not manufacturer's defects.

Shading:  normally the fault of the manufacturer's printing process.
1.  Edge shade:  where there is a color variation from one side of the sheet to the other, with plain all over designs and some textural type designs the technique of reverse hanging can be applied. This involves reversing every other strip to match up shading variations.
2.  Shade roll to roll:  this is where there is a color variation between rolls in the same batch number. This product shouldn't be installed and should be taken back to the supplier for replacement.
3.  Uneven emboss:  where the embossment of the wallcovering is deeper or lighter on one edge, this will give an effect of shade variation. This is normally most prevalent when looking along a finished wall where the light dark variation is most conspicuous.

Trimming Errors:  caused by manufacturer's cutting error.  These may be discovered by comparing the patterns of each roll, and insuring they are identical especially where they meet the edges of the wallpaper.
1.  Over-trimming is a result of too much of the wallpaper being trimmed away. When an excess amount of material has been trimmed away, there is no way to compensate for the missing pattern. If it is noticeable at a glance or is unacceptable, you should return the wallpaper to the retailer for replacement.
2.  Under-trimming is the complete opposite to over-trimming. This means not enough of the wallpaper has been trimmed away which results in a slight double image forming at the seam. This excess may be trimmed at the work table using a straight edge and razor, or may be "double cut" on the wall.

Printed on a bias or cut on a bias:  where the print is cut or printed on a slight diagonal so that the pattern drops down about 1/4 inches on every sheet. This error makes for bad ceiling lines.

Out of register:  where multi-pass printing of a wallpaper design is out of alignment.  For example, the out line of a leaf is printed first, then the inside green part. The inside green part is out side of the outline. Or the yellow center of the flower is an inch off. Some times the print will be OK and then further into the pattern, it will start to go outside the lines again.  A good example of this type of error is the Sunday comics, where the color can sometimes appear outside of the lines.

Vinyl runs out on front of vinyl coated paper:  caused by acrylic coating running out during final coating process.  This would call for replacement of affected rolls.

Paste missing on prepasted paper:  if using additional wallpaper paste, this isn't a major concern.  If you use plain water to activate the paste or activators, then replacement would be prudent.

Ink spots:  caused by leaks and drips of colorant during the manufacturing process.  Depending on the location and severity, this type of error may be cause for replacement.

Drag lines in ink:  caused by the manufacturer when the paper runs through the various bars and rollers of the printing press.  These lines may either be blank lines resulting from scraping or ink colored lines due to still wet colorants coming in contact with the rollers of the press.

Ink runs out for certain colors:  simple factory error where the colorant level runs low and causes faded to no coloring in the pattern.  This defect will always be cause for replacement.

Delamination:  this is a manufacturing error that can effect various substrates.  It is caused by improper lamination of the ground material to the substrate.  Some of these errors may be repairable during the installation process, but others may require the replacement of the defective materials.  Sometimes this error may be caused by improper booking time during the installation process.

Paste on front and vinyl on back of vinyl coated paper:  normally this is caused by factory errors relating to the reverse installation of the paper into the coating machines.  Paste on the front calls for a good washing during the installation process, though delicate wallpapers may require replacement with this defect.  Vinyl coating on the back of wallpaper generally requires replacement.

Ink runs when paper is rinsed with water:  this can be caused by improperly sealed wallpaper or delicate colorants used in the manufacturing process.  In the case of normal wallcoverings, this may be an indication of lack of coating on a coated paper and calls for replacement.  Some wallpaper is naturally delicate and installation instructions should pre-warn the installer that care is needed in the installation process to ensure that no liquid comes in contact with the surface layer.